Pan-tilt units are used to position, aim, steer or otherwise orient an imaging unit, such as a digital camera, into a desired direction by moving the imaging unit about two perpendicular axes. One common application is the field of surveillance and security, where an imaging unit is mounted to a pan-tilt unit that can be controlled or programmed to scan a desired area.
Pan-tilt movement is conventionally accomplished using separate motors that independently perform the pan and tilt operations. For example, a pan-tilt unit generally includes a pan motor for rotating the device about a pan axis, and a tilt motor for rotating the device about a tilt axis that is perpendicular to the pan axis.
In many applications, multiple imaging units in an imaging system are used to survey a particular area. Each imaging unit has a particular field of view, which is the area visible through the lens or lens system of the imaging unit. Because each camera has a particular field of view, there may be situations when the entire area cannot be viewed at the same time. This was particularly true in the past as imaging units used to be quite expensive. Consequently, having a pan-tilt unit on one or multiple cameras allowed fewer cameras to be used to survey an area. If the imaging system is designed so that certain combinations of pan and tilt values for imaging units allow the fields of view of some of the imaging units to overlap or come close, then the area can be scanned in an efficient manner.
Therefore, while these types of imaging systems can therefore be efficient and relatively inexpensive, there are certain problems with these systems. Accordingly, there is a need to provide improvements for imaging systems.